1. 1Department of Dermatology, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 4LP, U.K.
2. 2Department of Dermatology, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 4LP, U.K.
3. 3Department of Dermatology, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 4LP, U.K.
4. 4Department of Dermatology, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 4LP, U.K.